Method and apparatus for performing a minimally invasive total hip arthroplasty

ABSTRACT

A method and apparatus for performing a minimally invasive total hip arthroplasty. The apparatus may include a provisional femoral head allowing for radial placement thereof on a provisional femoral neck.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 10/952,301, filed on Sep. 28, 2004, published as U.S. PatentApplication Publication No. U.S. 2005/0043810, which is a divisional ofU.S. patent application Ser. No. 09/992,639, filed on Nov. 6, 2001, nowU.S. Pat. No. 6,860,903, which is a continuation-in-part of U.S. patentapplication Ser. No. 09/558,044, filed on Apr. 26, 2000, now U.S. Pat.No. 6,676,706, the disclosures of which are hereby explicitlyincorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates to total hip arthroplasty, and, moreparticularly, to a method and apparatus for performing a minimallyinvasive total hip arthroplasty.

2. Description of the Related Art

Orthopedic procedures for the replacement of all, or a portion of, apatient's joint have been developed over the last 30 years. Currently,the procedures used to prepare the bone and seat the implants aregenerally referred to as open procedures. For the purpose of thisdiscussion, the term open procedure will refer to a procedure wherein anincision is made through the skin and underlying tissue to fully exposea large portion of the particular joint surface. In the case of a totalhip arthroplasty, the typical incision required is approximately 25centimeters (10 inches) long. After the initial incision in the skin,the internal wound may be enlarged in order to fully expose the areas tobe prepared. While this approach provides surgeons with an excellentview of the bone surface, the underlying damage to the soft tissue,including the muscles, can lengthen a patient's rehabilitation timeafter surgery. While the implants may be well fixed at the time ofsurgery, it may be several weeks or perhaps months before the softtissues violated during surgery can fully heal.

SUMMARY

The present invention provides an improved method and apparatus forperforming a minimally invasive total hip arthroplasty. A total hiparthroplasty can be performed in accordance with the teachings of thecurrent invention utilizing two incisions, with the size of each of thewounds developed on the surface being substantially constant throughoutthe depth of the wound. The first incision is an anterior incisionapproximately 3.75-5 centimeters (1.5-2 inches) in length made in linewith the femoral neck and the central axis of the acetabulum. The secondincision is a posterior incision approximately 2.5-3.75 centimeters(1-1.5 inches) positioned to be generally in axial alignment with thefemoral shaft. Access from the posterior incision to the femoral shaftis provided by a tubular retractor.

The femoral head is severed from the femoral shaft and removed throughthe anterior incision. The acetabular cup is placed in the acetabulumthrough the anterior incision, while the posterior incision is used toprepare the femoral shaft to receive a femoral stem. After preparationof the femoral shaft, a trial reduction is performed, with a provisionalfemoral neck and provisional femoral head being operably positionedthrough the anterior incision. Once the trial reduction issatisfactorily completed, the hip is dislocated and the provisional headand neck are removed. A final femoral stem is then inserted through theposterior incision and positioned in the femoral shaft. Proceduresperformed through the posterior incision may be observed through theanterior incision and vice versa.

For the purpose of the following discussion, a total hip arthroplasty isdefined as a replacement of the femoral head with or without the use ofa separate acetabular component. The specific designs which can beutilized in accordance with the present invention include a total hipreplacement and a bipolar or monopolar endoprosthesis. The technique issuitable for cemented or cementless anchorage of the components.

In one form thereof, the disclosure provides a provisional femoral head,including a spherical body having a generally cylindrical internalaperture formed in a distal end of the spherical body, the internalaperture sized to accommodate a provisional femoral neck, the sphericalbody further including a first clamp aperture sized to receive a firstblade end of a clamp.

In another form thereof, the disclosure provides a provisional femoralhead, including a spherical body having a generally cylindrical internalaperture formed in a distal end of the spherical body, the internalaperture sized to accommodate a provisional femoral neck, the sphericalbody further including a first clamp aperture sized to receive a firstblade end of a clamp and a second clamp aperture sized to receive asecond blade end of the clamp, the first and second clamp aperturesextending through an exterior wall of the spherical body, the first andsecond clamp apertures forming a first opposing pair of clamp aperturesinto which the first and second blades of the clamp can be positioned tosecure the provisional femoral head to the clamp.

The provisional femoral head of the present invention advantageouslyallows for positioning thereof on a provisional femoral neck in a radialfashion with respect to the provisional femoral neck, thus facilitatingplacement of the provisional femoral head through the relatively smallsized anterior incision of the present invention.

The apparatus and method of the current invention advantageously allow atotal hip arthroplasty to be performed in a minimally invasive way,which hastens patient recovery.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a side elevational view of a patient illustrating a pair ofincisions made according to the current invention as well as theincision utilized in prior art procedures;

FIG. 2 is an anterior elevational view of a hip joint illustrating thefemoral neck axis;

FIG. 2A is an anterior elevational view illustrating the capsule of thehip joint;

FIG. 3 is an anterior elevational view of the femoral neck exposed byincising the hip capsule;

FIG. 4 is an anterior elevational view of the femoral neck with anosteotomy guide of one form of the current invention operably positionedto designate a cut line thereon;

FIG. 5A is a side elevational view of an alternative embodiment of anosteotomy guide in accordance with the present invention;

FIG. 5B is an elevational view thereof taken along the longitudinal axisof the handle;

FIG. 6 is an anterior elevational view illustrating the femoral head andneck severed along the cut line indicated by the osteotomy guide;

FIG. 7 is an anterior elevational view illustrating the removal of aportion of the femoral head and neck;

FIGS. 8A and 8B illustrate preparation of the acetabulum to receive theacetabular cup;

FIG. 9 is a side elevational view of an acetabular cup inserter relativeto a patient lying in the supine position;

FIG. 10 is an anterior elevational view of a portion of the cup inserterillustrated in FIG. 9 and a patient lying in the supine position;

FIG. 11 is a side elevational view illustrating the use of a curved awlto locate a posterior incision;

FIG. 12 is a side elevational, partial sectional view of an awl inaccordance with the present invention;

FIG. 13 is a perspective view illustrating the insertion of a posteriorretractor in the posterior incision;

FIG. 14 is a perspective, exploded view of one embodiment of a tubularretractor in accordance with the present invention;

FIG. 14A is a side elevational view of an alternative embodiment of thetubular retractor;

FIG. 15 is a perspective view illustrating the insertion of a guide wireinto the tubular retractor;

FIG. 16 is a perspective view illustrating reaming of the femoral shaft;

FIG. 17A is a perspective view of an end cutter;

FIG. 17B is a perspective view of a femoral reamer;

FIG. 18 is a side elevational, partial sectional view of an end cutterinserted into a tubular retractor of the present invention;

FIG. 19 is a perspective view of a rasp handle after inserting a raspinto the femoral shaft;

FIG. 19A is a perspective view illustrating an inserted rasp, with therasp handle removed, and with the cable used to affix the rasp to therasp handle protruding from the posterior incision;

FIGS. 20A and 20B are partial sectional views of the rasp handle;

FIG. 21 is an exploded view of the rasp handle and a rasp to beconnected thereto;

FIG. 21A is a partial elevational view along line 21A-21A of FIG. 21;

FIG. 22 is a perspective view illustrating placement of a provisionalneck of the present invention;

FIG. 23 is a perspective view of the provisional neck and mating forcepsof the present invention;

FIG. 24A is a partial sectional, radial elevational view of theprovisional neck;

FIGS. 24B and 24C are radial elevational views thereof;

FIG. 25 is a perspective view illustrating the insertion of a femoralstem with a protective bag through the posterior incision;

FIG. 26 is a perspective view illustrating alignment of the femoral stemwhile observing through the anterior incision;

FIG. 27 illustrates an incision into the femoral stem protective bagprior to insertion of the femoral stem into the femoral shaft;

FIG. 28 is a perspective view illustrating removal of the femoral stemprotective bag while inserting the femoral stem, with observationthrough the anterior incision;

FIG. 29 is a perspective view of a femoral stem insertion tool inaccordance with the teachings of the present invention;

FIG. 30 is a perspective view of a hip prosthesis which can be implantedaccording to the method of the current invention;

FIG. 31 is a plan view of a provisional neck and a provisional head inaccordance with the present invention;

FIG. 32 is a proximal plan view of the provisional head of FIG. 31;

FIG. 33 is a sectional view thereof;

FIGS. 34 and 35 are plan and sectional views, respectively, of analternative embodiment provisional head in accordance with the presentinvention;

FIGS. 36 and 37 are plan and sectional views, respectively, of anotheralternative embodiment provisional head in accordance with the presentinvention;

FIGS. 38-40 are plan views of a posterior retractor sleeve of thepresent invention;

FIG. 41 is a sectional view thereof;

FIG. 42 is a plan view of the posterior retractor sleeve of FIGS. 38-41and a mating occluder;

FIGS. 43 and 44 are end views of the occluder of FIG. 42; and

FIGS. 45-47 are perspective views illustrating insertion of theposterior retractor sleeve of FIGS. 38-41 into patient 40.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates one preferred embodiment of the invention, in one form, andsuch exemplification is not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

A total hip arthroplasty can be performed, according to the teachings ofthe current invention through two incisions, each no more than 5centimeters (2 inches) in length. An anterior incision is made along theaxis of the femoral neck, while a posterior incision is made generallyin axial alignment with the femoral shaft. Referring to FIG. 1, apartial illustration of a patient 40 including torso 52, buttock 50, andleg 48 illustrates prior art incision 42 as well as anterior incision 44and posterior incision 46 of the current invention. Prior art incision42 is approximately 25 centimeters (10 inches) long, while anteriorincision 44 and posterior incision 46 are each no more than 5centimeters (2 inches) in length.

According to the method of total hip arthroplasty of the currentinvention, patient 40 is initially placed in a supine position on aconventional operating table. Referring now to FIG. 2, with leg 48 in aneutral position, two prominent bony landmarks are palpated, theanterior superior iliac spine (ASIS) 59 and the greater trochanter 58 offemur 62. Ilium 64 and pubis 66 of hip 68 are shown to better illustratethe relevant area of the body. The approximate anterior incisionstarting point 71 is identified two fingerbreadths inferior and twofingerbreadths anterior to the tubercle of greater trochanter 58. Theapproximate finish point for the anterior incision is identified threefingerbreadths inferior and two fingerbreadths lateral to the anteriorsuperior iliac spine (ASIS) 59. With the use of a spinal needle, theappropriate starting point 71 and the path of the anterior incision areidentified by impaling the skin down to bone to confirm the central axis70 of femoral neck 60.

An oblique incision of approximately 3.75-5 centimeters (1.5-2 inches)is made from the starting site 71 toward the prominence of the greatertrochanter along the axis 70 of the femoral neck 60 and the central axisof acetabulum 54. The incision is extended along the same plane throughsubcutaneous tissues, exposing the underlying fascia lata. Theinternervous plane between the tensor fascia lata muscle and thesartorius is identified by palpation and developed by curved scissorsand blunt dissection. The sartorius can be made more prominent byexternally rotating the leg to apply tension on the muscle. Deep to thetensor fascia lata and the sartorius is an internervous interval betweenthe rectus femoris and the gluteus medius. This plane is developed byblunt dissection. A lateral retraction of the tensor fascia lata permitsa visualization of the capsule 74 of the hip joint as illustrated inFIG. 2A.

Leg 48 is externally rotated to create tension on capsule 74. Capsule 74is incised along the axis 70 (FIG. 2) of femoral neck 60 from theequator of femoral head 56 to the intertrochanteric ridge on the femur62. The capsular incision takes the form of an “H-shaped” window formedby incisions 72. The H-shaped window is formed by adding supplementaryperpendicular limbs around the equator of the femoral head 56 and thebase of the femoral neck 60 to the initial incision along the axis 70 offemoral neck 60. As a form of retraction, heavy sutures are used toprovisionally attach the capsular flaps 73 to the subcutaneous tissues.As illustrated in FIG. 3, retractors 76 are placed inside capsular flaps73 and underneath the superior and inferior borders of femoral neck 60to expose the entire length of femoral neck 60 from the inferior aspectof femoral head 56 to the intertrochanteric ridge. In one exemplaryembodiment, each retractor houses a light source and can also serve toanchor an endoscope. The retractors 76 thereby provide continuousvisualization and illumination of the wound.

Referring now to FIG. 4, a femoral cutting tool 86, e.g., an oscillatingsaw or a power burr is used to excise femoral neck 60. A customosteotomy guide 78 is placed through anterior incision 44 (FIG. 1) andfunctions to guide the femoral neck cut. Alignment portion 82 ofosteotomy guide 78 is aligned with the longitudinal axis of femur 62,while cut guide 84 is positioned on femoral neck 60. Handle 80 ofosteotomy guide 78 facilitates positioning and repositioning ofosteotomy guide 78 through anterior incision 44. After placement ofosteotomy guide 78, cut line 85 is scored as is known in the art.Osteotomy guide 78 is thereafter removed through anterior incision 44and femoral cutting tool 86 is inserted through anterior incision 44 andutilized to cut along cut line 85 and displace portion 88 (FIG. 6) fromfemur 62.

Retractors 76 are repositioned around the anterior and posterior rims ofthe acetabulum. As is known in the art, a custom curved cutting tool.(i.e., the “ligamentum teres cutter”) is passed behind femoral head 56to sharply incise the ligamentum teres, thus mobilizing cut portion 88as illustrated in FIG. 6. Cut portion 88 includes femoral head 56 aswell as a portion of femoral neck 60 (FIG. 4). Cut portion 88 isthereafter removed through anterior incision 44 with a custom femoralhead bone grasper 94 (FIG. 7). If there is difficulty removing cutportion 88 in one piece, it may be in situ morselized using cutting tool87 (FIG. 6), e.g., a power burr. Morsels 92 may then be removed throughanterior incision 44. Morselizing of cut portion 88 is accomplishedmaking cuts which substantially mirror the cuts in hip capsule 74.Irrigation and suction devices can be used to cool the bone andfacilitate the removal of bony debris in hip capsule 74. In oneexemplary embodiment, a fiber optic endoscope is placed into the hipjoint to confirm the complete removal of bony debris.

As illustrated in FIG. 8A, the fibro-fatty tissue within the cotyloidfossa of acetabulum 54 is removed with the use of, e.g., a high-speedacorn-tipped cutting tool 96, Rongeur forceps, and a curette.Thereafter, the acetabular labrum is trimmed with a scalpel. Asillustrated in FIG. 8B, acetabulum 54 is then progressively reamed withstandard acetabular reamer 98. Acetabular reamers within a predeterminedsize range are utilized until the optimal size of the acetabulum isreached. Sizing of the acetabulum is facilitated by the use ofpre-operative templates and radiographs as is known in the art. Onceagain, an endoscope can be used to aid in visualization during thereaming process. Typically the acetabulum is under reamed byapproximately 2 mm with respect to the diameter of the anticipatedacetabular cup so as to create an interference fit. High speedacorn-shaped cutting tool 96, and acetabular reamer 98 enter the bodythrough anterior incision 44.

After a trial fitting, a press-fit acetabular cup of the appropriatesize is firmly seated with cup inserter 100 as illustrated in FIG. 9 andimpacted into the acetabular recess as is known in the art. Properpositioning of the acetabular cup is achieved with a custom anteflexionand pelvic alignment guide. Patient 40 is placed in supine position onoperating table 102. Aligning rod 104 is aligned with the mid lateralaxis of torso 52 while main shaft 105 is maintained approximately 30°from operating table 102 for proper seating of the acetabular cup. Toaugment fixation of the cup, a flexible drill can be used to guide theplacement of one or more acetabular screws. The insertion of theacetabular liner is deferred until the proximal femur has been preparedfor the insertion of a trial stem. As illustrated by the anteriorelevational view of FIG. 10, patient 40 remains in the supine positionon operating table 102 (FIG. 9) while cup inserter 100 is utilized toseat the acetabular cup.

For preparation of the femur, the patient is repositioned with a padplaced under the ipsilateral hip. The hip is slightly flexed, adductedapproximately 30°, and maximally externally rotated. Retractors 76 arerepositioned around the medial and lateral aspects of femur 62.Alternatively, a self-retaining retractor with a light source attachmentand an endoscope holder can be positioned in anterior incision 44 toprovide constant visualization and illumination of femur 62.

With a scalpel or curved osteotome, the soft tissues along the anteriorsurface of femur 62 just inferior to the intertrochanteric ridge aresubperiosteally reflected to expose the bone for a width ofapproximately 1 cm. This sharp subperiosteal elevation continuessuperolaterally onto the anterior margin of the greater trochanter. Thenwith curved Mayo scissors a pathway is developed by blunt dissectionthat is directed superficially to the anterior fibers of the gluteusminimus towards buttock 50 (FIG. 11).

As illustrated in FIG. 11, awl 106 is inserted through the anteriorincision 44, directed superficially to the cleft in the gluteus minimus,and advanced into the soft tissues of buttock 50 until its pointeddistal end 108 can be palpated on the surface of the skin. Distal end108 of awl 106 is generally aligned with the longitudinal axis of femur62. At the point where distal end 108 is palpated, posterior incision 46of approximately 2.5-3.75 cm (1-1.5 inches) is made and extended throughthe subcutaneous tissues and fascia lata to expose the underlyinggluteus maximus. A tract to femur 62 is developed along the path createdby awl 106. The gluteus maximus is split bluntly in line with its fiberswith curved Mayo scissors. Into this pathway via posterior incision 46,custom elliptical posterior retractor 122, complete with its innersleeves, is threaded (FIG. 13) down to the osteotomized femoral neck. Inone exemplary embodiment, elliptical posterior retractor 122 includesposterior lip 128 (FIG. 14). In this embodiment, retractor 122 isthreaded down to the osteotomized femoral neck until posterior lip 128lies beneath the posterior intertrochanteric ridge. FIG. 14A illustratesan embodiment of rasp tunnel 130 without posterior lip 128. In analternative embodiment, each component of posterior retractor 122 (i.e.,guide tube 124, reamer tunnel 126, and rasp tunnel 130) is individuallyinserted and removed as necessary. In an embodiment in which guide tube124, reamer tunnel 126, and rasp tunnel 130 are individually insertedand removed into posterior incision 46, each individual tunnel may beprovided with a posterior lip similar to posterior lip 128 illustratedin FIG. 14.

In an alternative embodiment, posterior retractor sleeve 500 (FIG. 38)is used in lieu of elliptical posterior retractor 122. As illustrated inFIGS. 38-41, retractor sleeve 500 comprises a generally rectangular tubehaving proximal end 520, distal end 530, and apertures 510. Asillustrated, e.g., in FIGS. 38, 39, and 41, apertures 51 are generallyelongate apertures formed in opposing side walls of posterior retractorsleeve 500. Apertures 510 are oriented generally perpendicular to alongitudinal axis of posterior retractor sleeve 500. Both ellipticalposterior retractor 122 and posterior retractor sleeve 500 have a hollowinterior sized to accommodate passage of surgical instrumentstherethrough. For the purposes of this document, “surgical instruments”refers to hand-held tools or implements generally used by healthprofessionals for the performance of surgical tasks, including, e.g.,the various instruments utilized to prepare the femur to receive thefemoral stem.

Referring now to FIG. 42, occluder 540 includes extension 570 sized tobe placed within retractor sleeve 500. When retractor sleeve 500 isplaced about extension 570, flange 550 abuts proximal end 520 ofretractor sleeve 500. Occluder 540 includes handle 560 to facilitate usethereof to place retractor sleeve 500 in patient 40 as illustrated inFIGS. 45-47. As illustrated in FIG. 45, posterior retractor sleeve 500is placed about occluder 540, with flange 550 abutting posteriorretractor 500. Handle 560 is manipulated to place posterior retractorsleeve 500 in posterior incision 46 as illustrated in FIG. 46 and isthereafter utilized to turn posterior retractor sleeve 500 to the finalposition illustrated in FIG. 47. Occluder 540 is then removed fromposterior retractor sleeve 500 as illustrated in FIG. 47. In operableposition, apertures 510 of posterior retractor sleeve 500 are occupiedwith tissue of patient 40 to thereby maintain the position of posteriorretractor sleeve 500 within patient 40. The remainder of this documentrefers to use of elliptical posterior retractor 122, however, retractorsleeve 500 can be utilized in lieu of posterior retractor 122 to provideaccess to femur 62 through posterior incision 46.

Referring now to FIG. 15, blunt tipped guide wire 146 is insertedthrough guide tube 124 of posterior retractor 122 and advanced intofemoral canal 148. While FIG. 15 illustrates guide tube 124 nested inreamer tunnel 126 and rasp tunnel 130, guide tube 124 may be directlyinserted through posterior incision 46. If the cancellous bone of femur62 is too dense to permit insertion of blunt tipped guide wire 146, thena conical cannulated reamer or end mill is used to prepare the femoralmetaphysis. If a nested posterior retractor configuration is utilized,guide tube 124 must be removed so that the reamer can be insertedthrough reamer tunnel 126 of posterior retractor 122. Similarly, if anested configuration is not utilized, reamer tunnel 126 must be insertedinto posterior incision 46. In any event, blunt tipped guide wire 146 isinserted about halfway down femoral canal 148. The following detaileddescription of the invention makes reference to a nested posteriorretractor configuration. It will be understood by those skilled in theart that if the nested configuration is not utilized, each individualcomponent of posterior retractor 122 will be inserted and removedthrough posterior incision 46 as necessary.

FIG. 16 illustrates preparation of femoral canal 148 to receive rasp 204(FIG. 19). Guide tube 124 is removed from posterior retractor 122 andend cutter 150 (FIG. 17A) is inserted through reamer tunnel 126. FIG. 18illustrates end cutter 150 positioned within reamer tunnel 126. Endcutter 150 includes elongate aperture 160 through which guide wire 146passes and guides end cutter 150. End cutter 150 is actuated by any ofthe many actuating devices known in the art. After end cutting iscomplete, end cutter 150 is removed through reamer tunnel 126 and reamer151 (FIG. 17B) is inserted therethrough. Reamer 151 includes reamerguide aperture 161 through which guide wire 146 passes and guides reamer151 as it reams femoral canal 148. Reamers of progressive increase intheir outer diameter are sequentially placed over guide wire 146 andfemoral canal 148 is reamed until cortical “chatter” is felt. As isknown in the art, the optimal diameter of femoral canal 148 isprovisionally determined by preoperative templating. Some surgeons maychoose to avoid reaming of the femoral shaft and instead utilize abroach as is known in the art. A broach may be inserted in accordancewith the current invention as described hereinbelow with respect to raspinsertion.

After the correct diameter of femoral canal 148 is reamed out, reamertunnel 126 (FIG. 14) is removed from posterior retractor 122 so thatrasp 204 and rasp handle 212 (FIG. 19) can be inserted over guide wire146 to complete preparation of femur 62. Guide wire 146 is inserted intorasp guide aperture 214 and rasp handle guide aperture 202 to guide rasp204 to prepared femur 62. Impact surface 164 is struck, as is known inthe art, to place rasp 204 in femur 62. While rasp 204 is beingimpacted, the rotational alignment can be assessed by direct visualscrutiny of femur 62 through anterior incision 44. Furthermore,assessment of the alignment of rasp handle 212 with respect to thepatella, lower leg, and foot facilitates alignment.

Progressively larger rasps are inserted to achieve the optimal fit andfill in femur 62. Once the final rasp is fully seated, rasp handle 212is removed along with guide wire 146 and posterior retractor 122,leaving distal end 208 of flexible cable 192 (FIG. 19A) attached to theproximal end of rasp 204 and proximal end 194 of flexible cable 192protruding from posterior incision 46. The operation of rasp handle 212will be further explained below.

After the final rasp is seated in femoral canal 148, a trial acetabularliner is placed through anterior incision 44 and into the seatedacetabular cup with the use of a liner inserter as is known in the art.Provisional neck 222 is inserted through anterior incision 44 and lockedto the top end of the seated rasp, as illustrated in FIG. 22. A trialfemoral head is thereafter placed on the Morse taper of provisional neck222 through anterior incision 44. Referring to FIGS. 31-37, provisionalhead 400 is adapted for placement on provisional neck 222. Provisionalhead 400 includes a spherical body having a generally cylindricalinternal aperture formed of tapered portion 470 and proximal portion472. Provisional head 400 further includes cutout 450 positioned toallow radial placement of provisional head 400 on provisional neck 222as illustrated in FIG. 31. After provisional neck 222 traverses cutout450, provisional head 400 is axially displaced along proximal neck 222until snap ring 410 on provisional neck 222 engages snap ring groove 480on provisional head 400 and taper 460 on provisional neck locks withtaper 470 on provisional head 400. Clamp apertures 440 are positioned inprovisional head 400 to receive the blade end(s) of a clamp (not shown)utilized to position provisional head 400. Provisional head 400 furtherincludes vent hole 490 to allow bodily fluid and debris to be ejectedfrom the internal aperture of provisional head 400 when provisional head400 is positioned on provisional neck 222. FIGS. 34 and 35 illustrate analternative embodiment of provisional head 400 having shallower taperedportion 470′ relative to tapered portion 470 of the provisional headillustrated in FIGS. 31-33. FIGS. 36 and 37 illustrate anotheralternative embodiment of provisional head 400 in which distal end 420″forms a generally cylindrical extension from the spherical body ofprovisional head 400″. After placement of provisional head 400, the hipjoint is reduced for an assessment of stability of the hip joint andlimb length. Where necessary, a second assessment is made.

Once the trial reduction is satisfactorily completed, the hip isdislocated and the provisional head and provisional neck 222 areremoved. Rasp handle 212 is reinserted through posterior incision 46over the free end of flexible cable 192. Rasp handle 212 is advanceduntil it can be locked with the seated rasp so that impact surface 164can be impacted and the entire tool (i.e., rasp 204 and rasp handle 212)can be removed. The trial acetabular liner is removed through anteriorincision 44.

Via anterior incision 44, the final acetabular liner 252 (FIG. 30) isseated into acetabular cup 250 (FIG. 30) with a liner inserter thatpermits its impaction in place, as is known in the art. Femoral implant238 (FIG. 30) is anchored to femoral stem insertion tool 240 (FIG. 29)and placed through posterior incision 46. As illustrated in FIG. 25,femoral implant 238 is placed in protective, disposable bag 242 prior toits introduction into posterior incision 46. Protective, disposable bag242 keeps femoral implant 238 clean as it is inserted through posteriorincision 46. Note that FIG. 25 illustrates femoral implant 238 orientedas it will be when placed in femur 62. To insert femoral implant 238through posterior incision 46, femoral implant 238 must be rotated 180°from this position to prevent impingement on the body. Femoral implant238 is then rotated 180° after being completely inserted throughposterior incision 46.

FIG. 26 illustrates femoral stem 238 and bag 242 inserted throughposterior incision 46. When the tip of femoral stem 238 approaches theosteotomized femoral neck, the distal end of bag 242 is incised asillustrated in FIG. 27. Scalpel 246 is inserted into anterior incision44 to incise bag 242. As femoral stem 238 is driven into femoral canal148, bag 242 is progressively removed through posterior incision 46 asillustrated in FIG. 28. After femoral stem 238 is fully seated, femoralstem insertion tool 240 (FIG. 29) is removed through posterior incision46. Through anterior incision 44, the final femoral head is positionedon the femoral neck Morse taper using a standard holding device andsecured with a standard impaction tool and mallet. The hip is thenreduced and assessed for stability.

After appropriate antibiotic irrigation, the hip capsule and the softtissues are repaired with heavy sutures or staples. A suitable localanesthetic solution is injected into the closed hip joint as well as thecapsular layer and the subcutaneous tissues, allowing superiorpostoperative pain relief. The fascial layers, subcutaneous tissues, andskin of both anterior and posterior wounds are closed in a conventionalmethod and dressings are applied. A suction drain may be used at thediscretion of the surgeon.

Osteotomy guide 78, illustrated in use in FIG. 4, includes handle 80,alignment portion 82, and cut guide 84. In one exemplary embodiment, cutguide 84 and alignment portion 82 form a 60° angle. In one exemplaryembodiment, alignment portion 82 includes a tapered distal end asillustrated in FIGS. 5A and 5B. Osteotomy guide 78 is inserted throughanterior incision 44 and is positioned with alignment portion 82 beingplaced on femur 62 so that alignment portion 82 generally aligns withthe longitudinal axis of femur 62. Handle 80 protrudes through anteriorincision 44 and may be utilized to position osteotomy guide 78. Afterosteotomy guide 78 is properly positioned, cut guide 84 is utilized tomark cut line 85 on femoral neck 60 as illustrated in FIG. 4. Osteotomyguide 78 can be formed to function on either side of the body. FIG. 4illustrates an osteotomy guide designed to function on the right femur,while FIG. 5B illustrates an osteotomy guide operable to function on theleft femur.

As discussed supra, awl 106 (FIG. 12) is designed for insertion throughanterior incision 44 to locate posterior incision 46 (FIG. 11). Awlshaft 116 includes proximal end 110 designed for insertion into handle112. Handle 112 includes a longitudinal channel 120 into which proximalend 110 of awl shaft 116 may be inserted. Locking screw 118 is operablypositioned in handle 112 and may be actuated by locking knob 114.Locking knob 114 is utilized to place locking screw 118 in lockingengagement with proximal end 110 of awl 106. In one exemplaryembodiment, proximal end 110 of awl 106 includes a flat portion toengage locking screw 118 and facilitate the locking engagement of awlshaft 116 to handle 112. Awl shaft 116 further includes distal end 108.Distal end 108 is generally straight and is utilized to generally alignwith a longitudinal axis of femur 62 (FIG. 11). As illustrated in FIG.12, distal end 108 of awl shaft 116 includes a tapered end to facilitateinsertion of awl 106 through anterior incision 44 to locate posteriorincision 46. Additionally, distal end 108 of awl 106 may be of smallerdiameter than the body of awl shaft 116 as illustrated in FIG. 12. In analternative embodiment, awl 106 is formed in one piece and isdisposable.

Referring now to FIG. 14, posterior retractor 122 comprises three nestedparts. Guide tube 124 is nested in reamer tunnel 126 while reamer tunnel126 is nested in rasp tunnel 130. When posterior retractor 122 isthreaded into posterior incision 46, guide tube 124, reamer tunnel 126,and rasp tunnel 130 can be nested together to form a single unit. Rasptunnel 130 includes exterior threads 132 to facilitate threading ofposterior retractor 122 through posterior incision 46. Rasp tunnel 130includes rasp aperture 134 through which reamer tunnel 126 may beinserted and, in one alternative embodiment, posterior lip 128 forpositioning posterior retractor 122, as discussed above. Reamer tunnel126 includes flange 136 which is operable to retain the position ofreamer tunnel 126 within rasp tunnel 130. Reamer tunnel 126 includesreamer aperture 138 through which guide tube 124 may be inserted. Guidetube 124 includes a tapered distal end 140 to facilitate its insertioninto reamer aperture 138. Guide tube 124 includes guide wire aperture144 through which guide wire 146 (FIG. 15) may be inserted. Reameraperture 138 is sized to allow insertion of end cutter 150 (FIG. 18), orfemoral reamer 151 as discussed above. As illustrated in FIG. 18, guidetube 124 is removed from reamer tunnel 126 and end cutter 150 isinserted through reamer aperture 138. Longitudinal reamer aperture 138is sized to accommodate guide cylinders 156 and to thereby provideguidance and stability to end cutter 150. After end cutting (andreaming, if desired) is complete, reamer tunnel 126 is removed from rasptunnel 130. Rasp aperture 134 is sized to accommodate insertion of rasp204 as well as cannular insertion member 168 of rasp handle 212. Forsurgeries which do not utilize reaming, the posterior retractor cancomprise a rasp tunnel with a guide tube nested therein and not includea reamer tunnel as described above. As described above, posteriorretractor 122 is not always utilized in its nested configuration. In oneexemplary embodiment, guide tube 124, reamer tunnel 126, and rasp tunnel130 are each inserted into and removed from posterior incision 46 asnecessary.

Referring now to FIG. 21, rasp handle 212 includes cannular insertionmember 168, impact surface 164, grip 166, elongate guide aperture 202,elongate aperture 200, and engagement channel 190. Rasp 204 includes anaperture 216 sized to receive and retain retainer 210 on distal end 208of flexible cable 192. Retainer 210 is placed in aperture 216 andflexible cable 192 follows cable channel 217 to exit rasp 204. Proximalend 194 of flexible cable 192 is inserted through elongate aperture 200of cannular insertion member 168 and distal rasp engagement guide 206 ispiloted to guide channel 215 of rasp 204. After exiting the proximal endof elongate aperture 200, proximal end 194 of flexible cable 192 may bereceived in engagement channel 190. Engagement channel 190 is sized toaccommodate and retain retainer 196. After retainer 196 is operablypositioned in engagement channel 190, grip 166 may be actuated totension flexible cable 192.

Referring now to FIG. 20B, retainer 196 is operably positioned inengagement channel 190. Attaching means 184, such as, e.g., rivets,belts, etc. are utilized to affix biasing elements 172 to grip 166 andinternal handle surface 182. Grip 166 is outwardly biased by handlebiasing elements 172 and pivots about pivot point 198. Grip 166 includestensioning member 188 and ratchet 174. Ratchet 174 is designed forengagement with tapered end 186 of pawl 176. Pawl 176 includes pawlflange 178. Spring 180 engages internal handle surface 82 and pawlflange 178 to bias pawl 176 toward cannular insertion member 168.Actuation of grip 166 against the biasing force of biasing elements 172rotates grip 166 about pivot point 198, causes ratchet 174 to come intooperative engagement with tapered end 186 of pawl 176, and causestensioning member 188 to contact flexible cable 192. FIG. 20Aillustrates grip 166 retained by pawl 176 in the closed position. Asillustrated, tensioning member 188 contacts and tensions flexible cable192, thus locking rasp 204 to rasp handle 212. Lock disengagement knob170 can be pulled against the biasing force of spring 180 to unlock grip166.

Referring now to FIG. 23, provisional neck 222 can be locked to rasp 204utilizing forceps 220. Forceps 220 include blade ends 230, 232. Bladeends 230, 232 are sized for insertion into provisional head apertures234, 236, respectively (FIGS. 24B and 24C). As illustrated in FIG. 24A,provisional neck 222 includes locking cylinder 224 and spring 228.Spring 228 upwardly biases locking cylinder 224. Upon insertion intoapertures 234, 236, blade ends 230, 232 can contact tapered portion 226of locking cylinder 224. Actuation of blade ends 230, 232 againsttapered portion 226 causes locking piston 224 to move in a directionopposite to the biasing force of spring 228. Provisional neck 222 isclamped to forceps 220 and slid in a radial direction into provisionalneck engagement area 218 (FIGS. 21 and 21A) on rasp 204. Afterprovisional neck 222 is fully slid onto rasp 204, forceps 220 may bereleased, thereby allowing locking piston 224 to return to its lockedposition under the biasing force of spring 228. Rasp 204 includescircular cut outs 217 which can be engaged by locking cylinder 224 tolock provisional neck 222 in place.

Channels 225 (FIG. 24A) on provisional neck 222 accommodate protrusions219 (FIG. 21) on rasp 204. Provisional neck 222 is slid onto rasp 204with protrusions 219 occupying channels 225 of provisional neck 222.Stop 223 of provisional neck 222 abuts protrusions 219 when provisionalneck 222 is completely slid onto rasp 204. When stop 223 abutsprotrusions 219, locking cylinder 224 may be locked (i.e., forcepsblades 230, 232 released) so that locking cylinder 224 engages circularcut outs 217, locking provisional neck 222 to rasp 204.

While the method of the current invention has been described withreference to a particular hip prosthesis, this is not meant to belimiting in any way and it will be understood that the method of thecurrent invention could be used with many prosthetics, including, e.g.,a cementless prosthesis, a hybrid prosthesis having a cemented stem anda cementless acetabular cup, a cemented prosthesis having both acemented stem and a cemented acetabular cup, or an Endo prosthesis forreplacing only the femoral head. In a procedure in which a cementedfemoral stem is utilized, the bone cement will generally be insertedthrough the anterior incision. It should also be understood by thoseskilled in the art that in a smaller patient the method of the currentinvention could be performed entirely through the anterior incision withno need to make a posterior incision as described above.

While this invention has been described as having an exemplary design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

1. A provisional femoral head, comprising: a spherical body having agenerally cylindrical internal aperture formed in a distal end of saidspherical body, said internal aperture sized to accommodate aprovisional femoral neck, said spherical body further including a firstclamp aperture sized to receive a first blade end of a clamp.
 2. Theprovisional femoral head of claim 1, wherein said spherical bodyincludes a cutout intersecting said internal aperture.
 3. Theprovisional femoral head of claim 2, wherein said cutout is sizedwhereby a provisional femoral neck can traverse said cutout to bepositioned within said internal aperture.
 4. The provisional femoralhead of claim 1, wherein said cylindrical internal aperture defines acurved interior wall of said spherical body.
 5. The provisional femoralhead of claim 4, further including a recess formed in said interiorwall, said recess sized to accommodate a projection on the provisionalfemoral neck, whereby the provisional femoral head and the provisionalfemoral neck are engaged in an interference engagement.
 6. Theprovisional femoral head of claim 5, wherein said interferenceengagement comprises a snap-fit engagement.
 7. The provisional femoralhead of claim 5, wherein said recess extends at least partiallycircumferentially around said curved interior wall.
 8. The provisionalfemoral head of claim 5, wherein said projection extends at leastpartially circumferentially around the provisional femoral neck.
 9. Theprovisional femoral head of claim 1, further comprising an extensionportion extending from said spherical body and further defining saidcylindrical internal aperture.
 10. The provisional femoral head of claim9, wherein said extension portion comprises a substantially cylindricalextension portion.
 11. The provisional femoral head of claim 1, furthercomprising a second clamp aperture sized to receive a second blade endof said clamp, said first and said second clamp apertures extendingthrough an exterior wall of said spherical body, said first and saidsecond clamp apertures forming a first opposing pair of clamp aperturesinto which said first and said second blades of said clamp can bepositioned to secure the provisional femoral head to said clamp.
 12. Theprovisional femoral head of claim 11, further comprising a third clampaperture and a fourth clamp aperture, said third and said fourth clampapertures forming a second opposing pair of clamp apertures.
 13. Theprovisional femoral head of claim 1, further comprising a vent aperturefluidly connecting said internal aperture and a proximal end of saidspherical body.
 14. A provisional femoral head, comprising: a sphericalbody having a generally cylindrical internal aperture formed in a distalend of said spherical body, said internal aperture sized to accommodatea provisional femoral neck, said spherical body further including afirst clamp aperture sized to receive a first blade end of a clamp and asecond clamp aperture sized to receive a second blade end of said clamp,said first and said second clamp apertures extending through an exteriorwall of said spherical body, said first and said second clamp aperturesforming a first opposing pair of clamp apertures into which said firstand said second blades of said clamp can be positioned to secure theprovisional femoral head to said clamp.
 15. The provisional femoral headof claim 14, further comprising a third clamp aperture and a fourthclamp aperture, said third and said fourth clamp apertures forming asecond opposing pair of clamp apertures.
 16. The provisional femoralhead of claim 14, wherein said spherical body includes a cutoutintersecting said internal aperture.
 17. The provisional femoral head ofclaim 16, wherein said cutout is sized whereby a provisional femoralneck can traverse said cutout to be positioned within said internalaperture.
 18. The provisional femoral head of claim 14, wherein saidcylindrical internal aperture defines a curved interior wall of saidspherical body.
 19. The provisional femoral head of claim 18, furtherincluding a recess formed in said interior wall, said recess sized toaccommodate a projection on the provisional femoral neck, whereby theprovisional femoral head and the provisional femoral neck are engaged inan interference engagement.
 20. The provisional femoral head of claim14, further comprising a vent aperture fluidly connecting said internalaperture and a proximal end of said spherical body.